Quarter	Percent
1999-04-01	44.4
2000-04-01	44.8
2001-04-01	45.5
2002-04-01	45.3
2003-04-01	45.1
2004-04-01	44.5
2005-01-01	45.5
2005-04-01	45.3
2005-07-01	45.5
2005-10-01	45.9
2006-01-01	46.1
2006-04-01	46.6
2006-07-01	47
2006-10-01	47.1
2007-01-01	47
2007-04-01	47.6
2007-07-01	48.1
2007-10-01	48.5
2008-01-01	47.9
2008-04-01	47.8
2008-07-01	48.9
2008-10-01	49.4
2009-01-01	48.4
2009-04-01	48.8
2009-07-01	48.8
2009-10-01	50.2
2010-01-01	49.1
2010-04-01	49.5
2010-07-01	49.7
2010-10-01	50.1
2011-01-01	50.2
2011-04-01	50.9
2011-07-01	51.4
2011-10-01	51.5
2012-01-01	50.7
2012-04-01	51.1
2012-07-01	51.5
2012-10-01	51.6
2013-01-01	51.6
2013-04-01	51.9
2013-07-01	52.1
2013-10-01	52
2014-01-01	51.9
2014-04-01	52.2
2014-07-01	52.5
2014-10-01	52.4
2015-01-01	52.1
2015-04-01	52.3
2015-07-01	52.5
2015-10-01	52.7
2016-01-01	53.2
2016-04-01	53.2
2016-07-01	53.7
2016-10-01	54.1
2017-01-01	53.5
2017-04-01	53.7
2017-07-01	54.2
2017-10-01	54.7
2018-01-01	53.9
2018-04-01	53.9